Brake drum grinding machine



P 1934' H. G. MORRIS ET AL BRAKE DRUM GRINDING MACHINE Filed Nov. 3. 1932 2 Sheets-Sheet l BMW .CMorr wi W Sept. 11, 1934. H. G. MORRIS El AL 1,973,264

BRAKE DRUM GRINDING MACHINE Filed Nov. 5, 1932 2 Sheeiis-Sheet 2 43 Z] HQMOf/"ls Patented Sept. 11, 1934 UNITED STATES PATENT OFFICE City, Kan:

or: of one-fourth to Victor De Backer, Kansas City, lilo.

Application November 3, 1932, Serial No. 641,100

18 Claims.

This invention relates to improvements in grinding machines and pertains particularly to a machine which is designed to grind and refinish the surfaces of brake drums.

The primary object of the present invention is to provide a machine which is entirely automatic in its operation, after it has had a motor vehicle brake drum mounted thereon, to grind off and refinish the brake band engaging surface thereof.

The practice heretofore followed in refinishing motor vehicle brake drums has been to remove the wheel and drum from the car and mount the same'upon a lathe with a cutting tool which is operated to cut down the scarred face of the drum to a new surface. Such a method requires expensive and unusually large lathe machines and requires a considerable amount of time and is, therefore, an altogether expensive procedure.

The present invention contemplates the pro- 0 vision of a portable machine which is operated by an electric motor and upon which the wheel and brake drum may be mounted, after which the machine is set in operation and requires no further attention.

The invention further contemplates the provision of a machine whereby a turning abrading wheel is employed which while turning around in the brake drum is also constantly rotated so that a thorough grinding and evening of the inner surface of the drum is effected.

Another object of the invention is to provide a novel compact machine for the purpose described, which is readily adaptable to wheels and brake drums of different diameters.

The invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawings forming part of this specification, with the understanding, however, that the invention is not confined to any strict conformity with the showing of the drawings but may be changed or modified so long as such changes or modifications mark no material departure from the salient features of the invention as expressed in the appended claims.

.In the drawings:--

Figure l is a view in side elevation of the machine embodying the present invention, parts thereof being'in section;

Figure 2 is a view in top plan of a portion of the machine, with parts thereof broken away;

Figure 3 is a sectional view taken substantially upon the line 33 of Figure 1;

Figure 4 is a sectional view taken substantially 5 upon the line 4-4 of Figure 3;

Figure iiisasectional view taken partly through one side of the motor and a portion of the adjacent structure, upon the plane indicated by the line 5-5 in Figure 1.

Referring now more particularly to the draw- 00. ings wherein like numerals of reference indicate corresponding parts throughout the several views, the numeral 1 indicates generally the motor by which the present machine is operated. This motor is mounted on the under side of a head plate or body plate 2 which is relatively long as shown and which is formed at the end opposite that end to which the motor 1 is attached, to provide the central bearing 3. The body of the motor at the side opposite that to which the body plate 2 is connected, is formed to provide a dove-tail rib & which slidably engages in a similarly formed groove in the head 5 which forms an integral part of the top end of the normally vertical supporting arm 6. This rib 4 extends longitudinally of the motor so that the arm 8 may be adjusted thereon toward or away from the work as will be hereinafter more fully described.

The arm 6 has upon its inner face the two clamp jaws 7 each of which carries a screw 8 which passes through and is slidable in a slot 9 formed and longitudinallyof the arm 6.

Friction plates 10 lie across the outer face of the arm 6 and have the screws 8 extended therethrough and against these plates bear the thumb nuts 11 which are threaded onto the screws 8 in the manner illustrated. By means of these thumb nuts the jaws 7 may be firmly se-'- cured in adjusted position relative to one another for holding the felly of a wheel, the brake to drum of which is to be refinished.

Such a wheel is indicated generally by the numeral 12 and has, as shown, the brake drum 13 secured thereto and the tapered shaft bearing 14 which aligns with a similar hearing 15 forming a part of the drum.

Fixed against rotation in the bearing collar 3 is one end of a shaft 16 through the center of which is formed a grease passage 1'1 which at the upper end is connected with a suitable ccupling 18 by means of which grease may be forced into the passage 1'7. This passage is provided with the several lateral outlet openings 19 through which the grease is forced to lubricate the several surrounding parts as will behereinafter more 106 fully seen.

The lower end of the shaft 16 has fixed thereto a collar 20 and beneath this collar the shaft is screw-threaded as indicated at 21 for detachable connection with a tapered centering pin 22 which positions in and frictionally engages the bearings 1415 of the wheel and brake drum.

In the manufacture of the present machine a number of these pins 22 will be provided which will be of different diameters so that the machine may be used for grinding brake drums having bearings 15 of different diameters.

Secured to the under side of the body plate 2 is a depending bracket 23 with which is integrally formed the bearing sleeve 24 which extends at right angles to the bracket as shown and is aligned with the center of the armature of the motor 1 so that the extended shaft 25 of the armature may pass therethrough. At the forward end of the sleeve 24, the same is enlarged to receive the anti-friction bearing structure 26 and at this end of the sleeve the shaft 25 carries a bevel gear 27.

There is also mounted upon the shaft 25 the worm 28. Meshing with this worm is a worm gear 29 which is carried upon the shaft 30. This. shaft is mounted in suitable bearings 31 which are preferably supported by the bracket 23 as illustrated and at the opposite end of the shaft from the worm gear 29 there is mounted the worm 32.

Surrounding the shaft 16 is a hollow shaft 33 upon the upper end of which is fixed the large worm wheel 34 which meshes with the worm 32. The lower end of this shaft 33 is located adjacent the collar 20 and passes through and is secured to a horizontally disposed two-part arm which is indicated as a whole by the numeral 35.

This arm is in the form of an elongated flat plate and is made up of the inner half 36 and the outer half or head portion 37.

These two halves of the arm are connected together by means of the pair of spaced rods 33 which are secured at one end in the edge of the head 37 which opposes the inner portion 36 and slidably extend through passageways 39 formed in the inner half 36 of the arm upon opposite sides of the longitudinal center thereof.

Interposed between the halves 36 and 37 of the arm and mounted upon the rods 38 are the collars 40 and positioned between these collars and the adjacent edge of the half 36 is an expansion spring 41 which normally tends to force the two halves of the arm apart.

The outward movement of the head 37 from the inner half 36 of the arm is controlled by the set screws 42 which are threaded into suitable apertures in the inner half of the arm in positions where, when threaded in, they will frictionally engage the rods 38 and hold the same against movement.

The shaft 16 and the tubular shaft 33 pass through the end of the half 36 of the arm which is remote from the head and the tubular shaft 33 is secured to the arm as previously stated.

Surrounding the shaft 33 and located in a suitable recess in the underlying portion of the arm 35 is an anti-friction bearing 43. This bearing 43 carries a second tubular shaft 44 and a worm gear 45 which is secured thereto. At its upper end this second tubular shaft 44 carries the bevel gear 46 which meshes with the bevel gear 27.

The inner tubular shaft 33 is provided with suitable apertures in alignment with certain of the passages 19 of the shaft 16, as indicated at 47, by means of which lubricant may pass outwardly to lubricate the contacting surfaces of the two tubular shafts.

The arm 35 which is'flxed to the tubular shaft 33 to be turned therewith, carries the several laterally extending ears 48 each of which is centrally aperturedand formed to receive an antifriction bearing 49. ings are in alignment and their centers are paral lel with the arm 35. As shown one of the ears 48 is carried by the head portion 37 of the arm-35 while the others are carried by the inner portion or half 36.

' Extending through and rotatably mounted in the bearings 49 is a reciprocable and rotary shaft 50. This shaft has mounted thereon a worm gear 51 which is provided with a floating key which couples it with the shaft whereby the movement of the shaft lengthwise is permitted without affecting the position of the gear.

Mounted upon the end of the shaft 50 which overlies the head 3'7 of the arm 35 is a worm 52. This worm is in mesh with the worm gear 53 which is carried by a vertical stub shaft 54 which passes through the anti-friction bearing 55 carried by the head portion 37 of the arm 35. The upper end'of this shaft 54 has secured thereto the collar 56 so that it is prevented from moving downwardly through the bearing 55.

Secured to the lower end of the stub shalf 54 beneath the head 37 is an abrading wheel 57, such, for example, as an emery wheel or the like.

In the operation of the present machine the drum carrying wheel 12 is fitted over the center spindle 22 so that the latter fits snugly in the hub bearing 14 of the wheel and the bearing 15 of the drum. The arm 6 is then moved inwardly toward the felly of the wheel and the clamps 7 moved together until they firmly engage opposite edges thereof. The wheel and drum will then be flrmly held in the proper position for the drum to be operated upon by the abrading wheel 57 which is located therein andwhich has its periphery resiliently held in contact with the flange portion thereof by the springs 41 of the arm 35.

Upon energizing the motor 1 rotary movement will be imparted directly from the shaft 25 to the outer tubular shaft 44 which, being coupled with the shaft 50, will cause the rotation of the abrading wheel 57 about the axial center of the shaft 54 by which it is turned. At the same time power will be transmitted from the worm 28 to the worm wheel 34 and the irmer tubular shaft 33, turning the latter to cause the arm 35 to swing about the shaft 16. It will thus be seen that the abrading wheel 57 will be moved around over the inner surface of the drum 13 while the latter is rotating so that the abrading operation will be performed upon the entire inner surface of the drum flange.

By loosening the set screws 42 the springs will operate to maintain constant contact between the wheel 57 and the flange of the brake drum. If, however, it is desired to true up the drum, the set screws 42 may be fixed after placing the abrading wheel into contact with the drum flange at the point farthest removed from the center thereof and it will then be seen that the surface areas which are not of the same radial distance from the center of the drum will be cut down and the entire inner surface reduced to a fixed diameter.

The shaft 54 which carries the abrading wheel 57 is vertically adjustable so as to facilitate the proper positioning of the abrading wheel with respect to the drum which is to be ground. This These anti-friction bearin the desired direction and resecured by retightening the screw.

The proper positioning of the wheel and drum upon the centering cone or pin 22 is also facilitated by reason of the locking nut 21' which is threaded upon the lower end of the shaft 16 to maintain the cone or pin 22 in the position to which it may be adjusted upon this shaft. The lower end of the cone terminates in the axially extending screw 22' upon which is threaded the nut 22". This nut binds against the under side of the wheel and holds it firmly in place upon the pin in the manner illustrated.

' Where the wheel and drum hubs or bearings may be of such a size that the pin 22 will be too small in circumference to properly receive them there may be provided suitable tapered sleeves (not illustrated) to be slipped over the pin 22 to thus ,increase the diameter thereof. By this means suitable adjustment may be made of the size of the cone pin to accommodate any size of wheel and drum hub.

It will be readily apparent from the foregoing that with a machine of the present type brake drums upon wheels of different sizes within fixed maximum and minimum limits may be handled and the drums thereof trued up or smoothed down as desired.

It will also be apparent that the machine is of i a compact character and is adapted to be readily transported so that it may be taken from place to place for performing the drum truing opera.- tion.

- Having thus described the invention, what is claimed is:-

l. A brake drum grinding machine, comprising a fixed shaft, a tapered body detachably coupled with one end of the shaft and extending longitudinally therefrom, said body being designed to engage in the center of a drum, an arm member connected at one end with the shaft to swing its other end in a circular path with the shaft as a center. an abrading element rotatably mounted upon the said other end of the arm, means for effecting the swinging movement of the arm about the shaft, and means for effecting the rotation of the abrading element during the swinging of the arm said means for swinging the arm about the shaft and means for effecting rotation of the abrading element including a motor for simultaneously imparting power to both of said means.

2. A brake drum grinding machine, comprising an abrading element, means for moving said abrading element in a circular path concentric with a drum, means for rotating the abrading element simultaneously with the movement of the same along said circular path, and means for supporting a drum in a position concentric with the center about which the abrading element is moved said means for moving the abrading element in a circular path and rotating the same, including gear trains operable by a common motor.

3. A brake drum grinding machine, comprising an elongated tapered body designed to frictionally engage in the center of a drum, a shaft fixed at one end to said tapered body to extend longitudinally therefrom, means for engaging and holding the other end of the shaft, an arm connected at one end with the shaft to have its other.

end turned in a circular path thereabout, means for turning said arm, a rotary abrading element carried by the said other end of the arm, means for rotating the abrading element, and means between the ends of the arm for shifting said 4. A brake drum grinding machine, comprising a fixed shaft, means for securing one end of the shaft on the axial center of a brake drum, an arm having said shaft passing therethrough at one end thereof, an abrading element carried at the other end of the arm, means for swinging said arm around the shaft, and means for moving the abrading element radially with respect to its circular path of travel about the shaft as the element travels through said path, said means comprising a spring on each side respectively of the longitudinal center of said arm and intermediate the ends thereof.

5. A brake drum grinding machine, comprising a fixed shaft, means for securing one end of the shaft on the axial center of a brake drum. an arm having said shaft passing therethrough at one end thereof, an abrading element carried at the otherend of the arm, means for swinging said arm around the shaft, and means normally tending to urge the movement of the abrading element radially outwardly of its circular path of travel about the path said means comprising means for slidably maintaining said arm for longitudinal reciprocating, rectilinear movement and resilient means for moving said arm longitudinally as the same is swung around said shaft.

6. A brake drum grinder, comprising a shaft, means for securing one end of the shaft to the center of a brake drum to dispose the shaft axial- 1y thereof, a rotary tubular shaft having the first shaft passing therethrough. an arm member having the first shaft and said tubular shaft passing therethrough. connecting means between the arm and the tubular shaft whereby the arm may be turned by the tubular shaft about the first shaft. means for imparting rotary motion to the tubular shaft, and an abrading element carried by the arm for contact with an adjacent brakedrum during the rotation of the arm.

7. A brake drum grinder, comprising a shaft, means for securing one end of the shaft to the center of a brake drum to dispose the shaft axially thereof, a rotary tubular shaft having the first shaft passing therthrough, an arm member having the first shaft passing therethrough, connecting means between the arm and the tubular shaft whereby the arm may be turned by the tubular shaft about the first shaft, means including a motor for imparting rotary motion to the tubular shaft, an abrading element carried by the arm for contact with an adjacent brake drum during the rotation of the arm, said abrading element being rotatably mounted on the arm, and means driven by said motor for rotating the abrading element constantly during its period of movement with the arm.

8. A brake drum grinder, comprising a shaft, means for securing one end of the shaft to the center of a brake drum to dispose the shaft axially thereof, a rotary tubular shaft having the first shaft passing therethrough, an arm member having the first shaft passing therethrough, connecting means between the arm and the tubular shaft whereby the arm may beturned by the tubular shaft about the first shaft, means for imparting rotary motion to the tubular shaft, an abrading element carried by the arm for contact with an adjacent brake drum during the rotation of the arm, means whereby the abrading element may be shifted longitudinally of the arm and means establishing driving connection between said-means for imparting rotary motion to the tubular shaft and the abrading element, whereby the latter is rotated as the said arm is turned.

9. A brake drum grinder, comprising a shaft, means for securing one end of the shaft to the center of a brake drum to dispose the shaft axially thereof, a rotary tubular shaft having the first shaft passing therethrough, an arm member having the first shaft passing therethrough, connecting means between the arm and the tubular shaft whereby the arm may be turned by .the tubular shaft about the first shaft, means for imparting rotary motion to the tubular shaft, an abrading element carried by the arm for contact with an adjacent brake drum during the rotation of the arm, means whereby the abrading element may be shifted longitudinally of the arm, and resilient means normally urging the movement of the abrading element radially outwardly of the circular path through which it is moved by the arm.

10. A brake drum grinding machine, comprising a shaft, means for securing one end of the shaft to the center of a brake drum to dispose the shaft axially thereof, a tubular shaft having the first shaft passing therethrough, means for rotating said tubular shaft, an elongated arm member transversely divided to form an inner and an outer portion, connecting means between said inner portion and the tubular shaft whereby the arm will be turned upon rotation of the tubular shaft, connecting means between the inner and outer portions of the arm whereby movement of the outer portion is permitted relative to the inner portion, means for holding the outer portion in adjusted relation to the inner portion, and an abrading element carried by the said outer portion of the arm for engagement with a brake drum when the arm is rotated with the tubular shaft.

11. A brake drum grinding machine, comprising a shaft, means for securing one end of the shaft to the center of a brake drum to dispose the shaft axially thereof, a tubular shaft having the first shaft passing therethrough, means for rotating said tubular shaft, an elongated arm member transversely divided to form an inner and an outer portion, connecting means between said inner portion and the tubular shaft where by the arm will be turned upon rotation'of the tubular shaft, connecting means between the inner and outer portions of the arm whereby movement of the outer portion is permitted relative .to the inner portion, means for holding the outer portion in adjusted relation to the inner portion, an abrading element carried by the said outer portion of the arm for engagement with a brake drum when the arm is rotated with the tubular shaft, and resilient means interposed between the inner and outer portions of said arm whereby upon the release of the said holding means the said outer portion of the arm will be constantly urged radially outwardly of the circular path in which it is moved by the tubular shaft.

12. A brake drum grinding machine, comprising a shaft, means for securing one end of the shaft to the center of a brake drum to dispose the shaft axially thereof, a tubular shaft having the first shaft passing therethrough, means for rotating said tubular shaft, an elongated arm member transversely divided to form an inner and an outer portion, connecting means between said inner portion and the tubular shaft whereby the arm will be turned upon rotation of the tubular shaft, connecting means between the inner and outer portions of the arm whereby movement of the outer portion is permitted relative to the inner portion, means for holding the outer portion in adjusted relation to the inner portion, an abrading element carried by the said outer portion of the arm for engagement with a brake drum when the arm is rotated with the tubular shaft, said abrading element being rotatably mounted upon the said outer portion of the arm, and means for turning the abrading element while it is being moved in a circular path by the supporting arm.

13. A brake drum grinding machine, comprising a shaft, means for securing one end of the shaft to the center of a brake drum to dispose the shaft axially thereof, a tubular shaft having the first shaft passing therethrough, means for rotating said tubular shaft, an elongated arm member transversely divided to form an inner and an outer portion, connecting means between said inner portion and the tubular shaft whereby the arm will be turned upon rotation of the tubular shaft, connecting means between the inner and outer portions of the arm whereby movement of the outer portion is permitted relative to the inner portion, means for holding the outer portion in adjusted relation to the inner portion, an abrading element carried by the said outer portion of the arm for engagement with a brake drum when the arm is rotated with the tubular shaft, resilient means interposed between the inner and outer portions of said arm whereby upon the release of the said holding means the said outer portion of the arm will be constantly urged radially outwardly of the circular path in which it is moved by the tubular shaft, said abrading element being rotatably mounted upon the said outer portion of the arm, and means for turning the abrading element while it is being moved in a circular path by the supporting arm.

14. A brake drum grinding machine, ,comprising a shaft, means at one end of the shaft whereby the same is secured axially to a brake drum, a rotatable tubular shaft through which the first shaft passes, an arm connected with the said tubular shaft to be turned therewith, an abrading element carried by the arm to be turned about the first shaft and in contact with the brake drum, said abrading element being rotatable on the arm, a second tubular shaft surrounding and rotatable about the first tubular shaft, means for turning the tubular shafts, and a driving connection between the second tubular shaft and the abrading element whereby the latter will be rotated while being turned by the arm about the shafts.

15. A brake drum grinding machine, comprising a shaft, means at one end of the shaft whereby the same is secured axially to a brake drum, a rotatable tubular shaft through which the first shaft passes, an arm connected with said tubular shaft to be turned therewith, an abrading element carried by the arm to be turned about the first shaft and in contact with the brake drum, said abrading element being rotatable on the arm, a second tubular shaft surrounding and rotatable about the first tubular shaft, means for turning the tubular shafts, means whereby the abrading element is constantly resiliently urged radially outwardly of the circular path along which it is moved by the arm, and a driving connection between the abrading element and the second tubular shaft whereby the abrading element may be constantly rotated, said driving connection permitting the said radial movement of the element.

16. A brake drum grinding machine, comprising a vertically disposed shaft, a centering element extending longitudinally of the lower end of the shaft for engagement in the center of a brake drum, abody connected with the upper end of the shaft, an electric motor mounted upon the under side of the body, a vertical arm disposed beneath and supporting said motor, connecting means between the arm and said motor whereby the arm may be adjusted toward or away from said shaft, clamping means carried by said arm for engaging the felly of a wheel upon which the drum is mounted and through which a centering element passes, a horizontal arm, a rotary tubular shaft surrounding the first shaft and having said horizontal arm fixed thereto, an abrading element carried by the horizontal arm for movement in a circular path concentric with the shaft, means for adjusting said abrading element radially of the circular path in which it moves, and a driving connecting means between the tubular shaft and the motor whereby the tubular shaft will be rotated. V

HENRY GRADY MORRIS. GROVER CLEAVLAND ALLEN. 

